Many photoelectric elements are required to be encapsulated in use, so as to prevent their contact with ambient water vapor and oxygen.
At present, as a common encapsulation method, the photoelectric element is encapsulated by melting glass powder with laser to obtain a photoelectric package.
A photoelectric package comprises a first substrate, a second substrate and a photoelectric element set between the first substrate and the second substrate. During the encapsulation, the glass powder paste is disposed around the edges of the first substrate or the second substrate, and then is molten by laser so as to connect the first substrate to the second substrate fixedly.
In the course of the entire encapsulation, the temperature rises from a low temperature to a high temperature, and then drops to a low temperature again. The first and second substrates are generally high-temperature resistant glass substrates, which have an expansion coefficient of about 34.5×10−7/° C., whereas the commercially available glass powder typically has an expansion coefficient of 70×10−7/° C. to 80×10−7/° C. The difference therebetween is so large that stress is often produced during the change of the temperature. If the stress is not fully released in the fabrication process, it will result in distortion and damage to the glass sealing material.
Therefore, how to reduce the stress generated in the encapsulation process of photoelectric elements has become a technical problem urgently need to be addressed in the art.